This invention relates to a connector structure in which a second connector is fitted to an interior of a cylindrical receiving port of a first connector such that the first and second connectors can be electrically connected together in an inner region of the cylindrical receiving port.
In Japanese Patent Unexamined Publication (Kokai) No. Hei 8-153557, there is disclosed a connector structure in which a cylindrical fitting portion of a second connector mounted on a wiring circuit board is fitted to an interior of a cylindrical receiving port of a first connector such that they can be electrically connected together in inner regions of the respective cylindrical receiving ports.
The above connector structure has the following shortcomings. Because the second connector is circular, the square region substantially circumscribing the circle forms a dead space. This dead space badly degrades the mounting efficiency of a given electronic part on a wiring circuit board (first problem). In case of a portable telephone, for example, where miniaturization is a main target to be achieved, improvement is demanded.
Also, in the above Japanese Patent Unexamined Publication No. Hei 8-153557, a cylindrical receiving port of the first connector is provided with slits so that it can be dilated and contracted, and a cylindrical fitting portion of the second connector is pushed into the slit of the cylindrical receiving port so that an inwardly projecting locking projection formed on an end portion of the receiving port is locked to a locking groove formed in an outer peripheral surface of the cylindrical fitting portion, thereby retaining a connection between the first connector and the second connector.
Because of the above arrangement, this prior art device has the following additional shortcomings. Since the locking projection is locked to the locking groove by only resiliency of the receiving port component pieces defined between the slits, the locking projection is liable to be unlocked from the locking groove by tensile force. In order to prevent this unfavorable occurrence, it would be necessary to increase the locking force of the receiving port component pieces. However, if the locking force should be increased, the operational force for locking and unlocking the locking projection with respect to the locking groove would be overly increased (second problem).
In the prior art including the above, when the cylindrical fitting portion is fitted to an interior of the cylindrical receiving portion of the first connector, an ground contact is achieved at this fitting surface. Here again, if the operational force for fitting should be reduced, a reliable electrical connection would be degraded. If the fitting portion should be strengthened in order to reduce the operational force for fitting, the operational force for locking/unlocking would be overly increased as mentioned (third problem). This problem is attributable to the arrangement in which connection between the first connector and the second connector and ground thereof depend on the fitting portion.
The present invention has been accomplished in order to overcome the above-mentioned shortcomings of the conventional devices.